Multidecadal variability of the Tonle Sap Lake flood pulse regime

Tonle Sap Lake (TSL) is one of the world's most productive lacustrine ecosystems, driven by Mekong River's seasonal flood pulse. This pulse and its long-term dynamics under River basin's (MRB) fast socio-economic development climate change need to be identified understood. However, existing studies fall short sufficient time coverage or concentrate only on changes in water level (WL) that critical parameters influencing ecosystem productivity. Considering rapidly changing hydroclimatic conditions basin, it crucial systematically analyse multiple key parameters. Here, we aim do using observed WL data for 1960–2019 accompanied with several derived from a Digital Bathymetry Model. Results show significant declines inundation area late 1990s dry season whole year, top increased subdecadal variability. Decreasing (increasing) probabilities high (low) 2000–2019 have been found, comparison return period 1986–2000 (1960–1986). The mean cycle daily (wet) 2000–2019, compared 1986–2000, has shifted 10 (5) days. Significant correlations coherence between large-scale circulations (i.e., El Niño-Southern Oscillation (ENSO), Pacific Decadal (PDO) Indian Ocean Dipole (IOD)), indicate atmospheric could influenced different scales. Also, discharge at mainstream suggest anthropogenic drivers may impacted levels lake. Overall, our results declining since 1990s.